stat405

Style drills

Rewrite each code block to comply with the class style guide.

  1. Show answer.

    x < - c( 1,-2,3,-4,5,NA )
      y < - x * - 1
      y[ y>0 ]
    
  2. Show answer.

    n = 1
    mycondition <- round (runif (1,0,1,))
    if( mycondition ) {
        n <- n + 1
        print(paste("n =" , n , sep=" "))
    } else {
    print("false")
    }
  3. Show answer.

    # create a sequence from 1 to 50
    z <- seq(1,50)
    
    # test whether an observation is even
    even <- z%%2 = = 0
    
    # subset z by the test above
    z = z [even]
    
    # plot a histogram
    library( ggplot2 )
    qplot (z, geom="histogram", binwidth=1)
  4. Show answer.

    mat <- matrix( c( 34, 23, 53, 6, 78, 93, 12, 41, 99 ) ,nrow = 3)
    df <- as.data.frame (mat)
    names( df ) <- c("score_given_to_car_on_driving_test", 
     "score.given.to.van.on.driving.test", 
      "score-given-to-truck-on-driving-test")
  5. Show answer.

    library( ggplot2 )
      head(mpg)
    second_version_of_mpg <- mpg[ mpg$cyl = 6,]
    second_version_of_mpg$class <- as.character(mpg2$class)
    qplot(cty, hwy, data=second_version_of_mpg, geom="point", color=class ) +  geom_smooth( method = "lm", se=FALSE ) + opts (title="City vs. Highway MPG" )
  6. Show answer.

    mean <- function(x) {
    sum(x)/length(x)
    }